In a soup pot on medium high, brown the sausage. Add the carrots, and cook until carmelized; add the onion and cook until translucent. Add the celery and cook until translucent, along with the chile if so desired. Deglaze with stock or broth, before adding the rest, along with the lentils, tomatoes, bay leaves, garlic, and oregano. Bring to a gentle boil then reduce to low and cook, covered, for 1 hour or until lentils are tender. Salt and pepper to taste.